A Royal Marine’s death was “clearly avoidable” after he fell 100 feet into a gorge while taking part in a special forces selection exercise in Snowdonia a coroner said.

Ashley Charles Hicks slipped into a gorge as he and five other soldiers were heading towards a rendezvous point near Trawsfynydd pursued by other soldiers in October 2012.

The hearing at Caernarfon heard the gorge was not identified as a hazard by officers planning the exercise.

Recording that the 25-year-old died as a result of an accident North Wales deputy coroner Nicola Jones said: “The failure to identify the gorge in the planning stage is the most significant factor in this incident.

“Ashley Hicks would not have died if it had been identified and declared out of bounds.”

Giving evidence from behind a screen, Soldier N, who was in charge of planning the exercise and a member of the directing staff, said he had visited the area and inspected the various rendezvous points the soldiers were expected to arrive at.

But he added it was very difficult to identify the routes students would take.

He said the area had been used for a similar exercise in 2007 but although maps from that event were available no notes were passed onto him about any potential hazards.

Soldier AA, the assistant chief of staff at the MoD responsible for specialist units, was told by the coroner a detective had told the hearing maps had “ceunant” - the Welsh word for gorge and asked if they had sought a translation.

The soldier said they used symbology rather than words

The coroner said: “I realise its a language foreign to those organising and planning the exercise but its the language of this area

The officer said: “We are quite proud of our map reading ability. On this occasion that ability was not enough to prevent the non-identification of this hazard. We have taken steps to make sure that doesn’t happen again.”

Soldier AA was a member of the inquiry set up after the incident. He said the inquiry had identified lessons to prevent another death in similar circumstances.

These included setting up a two-way communication system with patrols who may be heading into dangerous ground and improving briefings he said.

The 25-year-old from Solihull was expected by his colleagues to pass the gruelling course and become a member of the elite SAS Regiment.

Soldier R, who was the SAS officer in charge of choosing new recruits, said Marine was in the top 10 students on the gruelling course.

The inquest heard that up to 250 people started each course and the pass rate was between 9-13%.

The officer said: "We would expect rather than hope someone of Ashley's quality would pass the course.

"Escape, evasion and survival are inherent skills a soldier must demonstrate to join this specialist unit."

Mr Hicks’ mother Virginia Lewis said after the inquest: “My family and I would like to thank the Royal Navy, Special Forces, Royal British Legion and counsel for their compassion and support in respect of the tragic death of our beloved son and brother which occurred in the service of his country.

“In particular we would like to extend our special thanks to his colleagues who risked their own safety to be with him till the end and the valiant efforts of the aircrew who risked their lives to rescue him.”